ESC size estimate

[sihinch]

I have a new EDF and want to know what size esc to use.

It is a 10 blade 70mm EDF. I'm using a 2900kV motor. I just tested it on 3S and it was approx 11v under load giving around 31A and 330watts.  But I want to run it on 4S.

Is the relationship between A and V linear? So if 11v gave 31A would 14.6v give 41A? I don't think it does, does it?

I want to know what size esc to use on 4S with the Changesun 70mm 10-blade EDF and 2900kV motor.

Thanks in advance for your help.

[thehaze]

I don't think it's linear. But I'm not 100%. Without all the parameters on the drive system it's hard to determine exactly what you will need. I guess the first question to ask is whether or not the motor can handle the extra voltage.

Usually I would select an ESC that can handle slightly more (10 to 20%) than the max allowed burst current of the motor.  Example, If the motor is rated for 55A max burst I'd go with 60A.

[sihinch]

Thanks Mike.  I did some digging around trying to remember which motor it was and where I got it from.  i remember now, it was from Toysoncis, and was recommended on RC Groups in the Flyjet X-83 thread.

http://www.toysonics.com/2836-2900kv-edf-outrunner-for-70mm.html

So the motor is rated to 44A max, so I'm going to go with a 60A esc.

Cheers,
S